Organic light emitting diodes (OLED) have become the third generation display technology following liquid crystal displays, because of display characteristics, such as active light emission, a large visibility angle, a wide color gamut, a short response time and a high contrast, and advantages, such as a light weight, a thin thickness and flexibility.
In the conventional technology, an organic light emitting diode pixel arrangement structure usually includes multiple pixels. Each pixel includes a red (R) sub-pixel, a green (G) sub-pixel and a blue (B) sub-pixel, and R, G, B sub-pixels are arranged repeatedly to form an array. R, G, and B sub-pixels are square, and a long side and a short side of the square are perpendicular or parallel to a horizontal line (the horizontal line is parallel to a transverse direction of a paper intuitively, a linear evaporation source is arranged along the horizontal line in an evaporation process, and a scanning direction in the evaporation process is perpendicular to the linear evaporation source).
A conventional organic light emitting diode pixel structure is greatly influenced by a shadow effect. In the evaporation process, since the linear evaporation source is arranged along the horizontal line, the scanning direction is perpendicular to the horizontal line, the evaporation source has an evaporation angle, and there is a gap between a mask plate and a glass substrate. In such a structure, the sub-pixel obtained by evaporating with the mask plate having an opening usually has a shadow with respect to the opening on the mask plate. The larger the shadow is, the larger a distance between the openings of the mask plate is, and thus an area of a metal between the openings is increased, and an aperture ratio (a ratio of a light-emitting area of a pixel to a total area of the pixel) is reduced. Therefore, the distance between the openings on the mask plate is increased, while a pixel resolution (PPI, Pixels Per Inch) is reduced.